Background:
Prior to attending the University of Michigan, I acquired
a BS in
Applied & Engineering Physics at
Cornell University.
My senior-level research involved the fabrication of
gratings and fresnel lenses via microcontact printing and
pattern transfer to self-assembled monolayers on Au
surfaces. I also did research at the
Lawrence Livermore National
Laboratory for a total of two years. I spent about
five months in the Inertial Confinement Fusion department
learning how to fabricate extremely efficient dielectric
gratings using holographic interference lithography. The
remainder of my time at Livermore was spent utilizing the
same interometric lithography technique to design
holographic bifocal contact lenses.

Current Research: As a student in
Applied Physics, I spent much of my first couple years
in the Kopelman group exploring several fields, the gamut
of which extends from chemistry to biophysics to optics.
While most of this ongoing "exploration" consists of
reading journal publications, juggling coursework, and
lots of speculation, I've also managed to do some
experimental labwork.

In general, I would like to study the interaction
between light and matter, with some specification to
biological material. Such an endeavor requires an
interdisciplinary approach comprised of a wide variety of
scientific fields. Thus, I am also interested in such
aspects as non-linear and ultrafast spectroscopy,
near-field optics, quantum optics and single-molecule
studies.

My primary interest lies in the field of optics and its
application to the study of biological media. Most recent
experiments have investigated the phenomenon of trapping
dispersive materials in an optical potential well formed
by a focussed laser beam. Such contraptions, also known as
"optical tweezers", are widely used to realize and/or
study, for example, motional characteristics of cellular
structures, mechanical properties of DNA, or the
manipulation of micro- and nano-scale probes. In
particular, I have been looking at the possibility of
enhancing tweezer forces by trapping absorptive particles
near resonance. Although the principal motive of this
study is to enable the intracellular manipulation of
PEBBLEs (sol gel and polymeric), there is great interest
in other particle types, including solid state crystals
and semiconductor nanostructures.

NEAR
RESONANCE TRAPPING

Research in the Kopelman
laboratory involves the creation of nano-scale biochemical
probes for sensing analyte concentrations within and
around cells. A smaller probe offers the advantages of
non-invasiveness, spatial resolution, response speed and
lower absolute detection limit. In order to manipulate
this smaller probe optically (i.e. with laser tweezers)
for measurements in and around single cells, one must
specifically trap the particle without perturbing the
surrounding environment. To achieve this specificity, we
proposed near-resonance trapping of absorptive particles.

The Classical Electron Oscillator(CEO) model provides a
simple description of the frequency-dependent complex
polarizability of a Rayleigh particle (d << lambda) in a
focused laser beam. Real and imaginary parts of the
polarizability are proportional to the gradient and
scattering forces, respectively. Similar relations occur
for components of the complex index of refraction in the
geometrical optics regime (d >> lambda). By frequency
tuning the trapping beam near the probe's absorption
resonance, one can maximize the gradient force and
minimize the scattering force, thus optimizing the single
beam gradient trap.

For more details on the theoretical aspects please
refer to the following publications: